It depends on what program you actually did. If it was a true diversion, then your case was dismissed. This would have been a true dismissal and there should be no record of a criminal conviction.
In a diversion program, you plead guilty. But, entry of the judgment into the record is deferred. You are then allowed to take part in some kind of program (usually drug rehabilitation). If you successfully complete the program, your case is dismissed and no conviction is entered into the record. Of course, if you fail to complete the program, then the judgment is entered into the record and you are convicted. In addition, you will be sentenced to whatever is the appropriate sentence for your crime.
However, you say that you did probation. That makes me think you didn't do a diversion program. It sounds like you simply pled guilty and were sentenced to probation instead of jail or prison.
If this is the case. If you successfully completed probation. If you were not sentenced to any jail or prison time and if you have committed no crimes since, you are eligible to apply for dismissal under penal code section 1203.4. You should hire a criminal defense lawyer to help you do this.
PC 1203.4 is often referred to as "expungement." This name, however, is misleading as it suggests that your conviction is permanently wiped off your record. It is not. Instead, if the court agrees, your case will be dismissed. However, unlike diversion, this is not a "true dismissal." After a successful 1203.4 dismissal, the conviction still shows on your record, but a notation is added indicating that the conviction was subsequently dismissed pursuant to PC 1203.4. This is what a background check will show.
After a PC 1203.4 dismissal, you may truthfully answer "No" to a question on an application for most jobs that asks if you have ever been convicted of a crime. However, if you are applying to join the military, are applying to become a law enforcement officer, or in some other cases you must disclose the conviction. For a complete explanation of whether or not the job you are applying for is one of these, you should consult an administrative law or employment law attorney. For all other jobs, as indicated above, you may answer "No." For these jobs, even if the prospective employer discovers the conviction in a background check, under the California Labor Code, he is forbidden from using that against you.
You should also note that, after a PC 1203.4 dismissal, if you apply for any kind of license from the State of California, you must disclose the conviction on your application. If the application form permits, you may then explain that the conviction was dismissed pursuant to PC 1203.4. A surprising number of jobs require you to get a state license, including such mundane things as becoming a barber. This could pose a problem for you if you are planning to apply to some kind of vocational or combined educational/vocational training or study program. I most frequently see this problem in the context of applying to nursing school. You don't need to have a clean record for the academic part of the program. But you will to do the clinical part, which involves interning as a nurse. And, of course you will eventually have to apply for a nursing license in order to practice. For these reasons, many nursing schools will not accept you if you have a criminal background, even if it's only one misdemeanor conviction that was dismissed under PC 1203.4.