Diversity is more than just the color of your skin, and that is evidenced by the wide array of students who attend Cal Poly. That being said, the majority of students here at Cal Poly is Caucasian. The administration as a whole has made an effort to make students of all ethnicities feel welcome at the University. Having friends with many different backgrounds is not uncommon. One thing that Cal Poly students realize is that even in an ethnically homogeneous group of people, there can still be much diversity. It isn't hard to find people of different cultures in class.
Another thing to be aware of is that there are many multicultural clubs and organizations. Some of these organizations are culture-specific (Chinese Students' Association, for example), but by no means culture-exclusive. These organizations welcome students unconditionally and even the seemingly homoegeneous clubs have more diversity than most people would anticipate. Conflicts regarding diversity usually surround issues of sexuality rather than race or gender. Fortunately, Cal Poly has the Pride Center on campus that supports students of any sexuality.