Unfortunately there's no graduation ceremony. The firies have one because they graduate as firies. Controllers don't graduate. They have to go out to the field and get a licence from CASA. By that stage, you and your course mates are scattered to the four winds and various training regimes, depending on which group you are allocated.
Passing out of the academy simply indicates that you have potential to make the (substantial) jump to safely handling live traffic. It's a big jump from meeting a basic standard on a 45 minute sim run, to doing it 7+ hours a day, day-after-day, to your OJTI's and checkie's satisfaction.