I'd keep celebrations low-key and personal. Don't worry about announcing your DD's graduation formally; the people who you really value will hear it organically from you or already know.
Gift-wise, why not make it an experience gift? A weekend trip somewhere she'd like to explore--maybe to take in a play or concert--would be a great way to celebrate the rite of passage of moving to university. Another idea is to buy a piece of tech kit that would help her in university, like an iPad with an infrared projected keyboard of a slim laptop to minimize the bulk of taking notes.
