Our son graduated last week and we had a great day.
There are no rituals or any particular etiquette, just do what you will all enjoy.
We had champagne before we left his flat, the department that he was graduating from laid on a lovely pre-graduation lunch, then we had coffee and strawberry tarts in the University Union, also laid on by the Students' Association this time. The ceremony was over ina flash, but we tok loads of photos, then after even more champagne, we went out to dinner in a lovely restaurant, my son's choice.
I am sure that you will find that local restaurants will be offering post- or pre- graduation meals, so hurry up and book.
Have a wonderful time and feel the pride as your daughter is 'capped'.