At my position (asst prof at regional state), I am 'the other'. I stick out from my colleagues, something that is generally acknowledged by students and faculty alike. I like my colleagues and they like me. Yet they view me with subtle suspicion.
Why? In my opinion, there are three reasons:
1. I have a diverse background, having studied in fields outside of psych, and having worked for years outside of academia. In contrast, every one of my psych colleagues got their BA in psych, MA in psych, and PhD in psych. They think like psych people, and I don't.
2. I hold the students to a high degree of accountability. This is in sharp contrast to my colleagues, who generally are concerned about 1) course eval numbers, and 2) not getting students upset. In short, I am considered 'tough', and not particularly cuddly.
3. I am politically conservative. My colleagues are all liberals. This political difference is manifest in a number of ways, but mainly in how the faculty comport themselves with the students. They regard themselves as "pro-student" (a phrase they frequently employ), are oddly maternal with them, and want to be friends with the students. In contrast, I view myself as their professor, the one who must administer grades that reflect their relative knowledge.
The point is that I represent 'diversity', if by that we mean a genuine alternative to the other faculty. My background, my ideas, my orientation - all quite different from my colleagues.
I'm also a straight, white man. My colleagues are a nice medley of cultural differences, but they all think (more or less) alike. And if we have a faculty search, I guarantee you they would look for someone who is 'diverse' in their sense - someone who looks different, but thinks exactly like they do.
BTW, if in the interview you are asked, "Tell us how you value and incorporate diversity into your classroom", make sure that you give the right answer.