I'm no good at gift suggestions, but since I just celebrated my birthday recently, maybe I could think of some things that I think people would like to receive. Here they are:
1. Books - For me, this is always a good choice, as long as I like the story of the book. Pick anything with a touch of romance and I'll love it. Haha.
2. Something Useful - It depends on the person's personality and hobbies. If your friend is studying veterinary medicine, then try looking at some veterinary graduation gifts. I'm sure your friend will appreciate it!
3. Chocolates/Cakes/Sweets - Everyone loves these, I think. :)
4. Anything that's personal!