The digital version of this article gives us a much better image, in color:  From the 5th paragraph:

But contrary to conservative rhetoric, studies show that going to college does not make students substantially more liberal. The political scientist Mack Mariani and the higher education researcher Gordon Hewitt analyzed changes in student political attitudes between their freshman and senior years at 38 colleges and universities from 1999 to 2003. They found that on average, students shifted somewhat to the left — but that these changes were in line with shifts experienced by most Americans between the ages of 18 and 24 during the same period of time. In addition, they found that students were no more likely to move left at schools with more liberal faculties.