Here are some articles with the statistics:
Racial Diversity: https://www.elon.edu/E/admissions/undergraduate/first-year-class-profile.html (They are getting better than year’s past, but the number of Asian-Americans at the school are especially low at 2%)
Pell Grants: http://hechingerreport.org/which-college-will-replace-wash-u-as-the-least-socioeconomically-diverse-in-the-country/
Socioeconomic diversity: https://www.nytimes.com/interactive/projects/college-mobility/elon-university (scroll down, the average family income is $208,300 and almost 80% of students come from the top 20%) <— this website is pretty cool, it tracks socioeconomic diversity (with rankings) across several schools and also upward mobility after college
There have also been a few College confidential posts about this and when you look at college review sites by students, diversity is often the number one thing that people say is lacking at the school aside from maybe dining, but that is common at many schools.