How to deal with a rude fellow student (in graduate school !?)?

I'm having trouble dealing with some fellow graduate students that seem to have regressed to high school. I don't know anything about clroom dynamics and I'm beginning to get worried about this because the only answers I got when I googled this question were about situations with high school students, not twenty-something adults. My problem consists of a few insensitive female (and some male) students who seem to get pleasure from embaring other students in front of the professors. For example, if a student raises his or her hand to ask a question, and the professor takes it lightly or he plainly doesn't like it, these girls start rolling their eyes and turning their faces away in a 'Valley girl' stereotype-style. The other day I made the mistake of going to one of the professor's office along with my ignment partner to talk to him about something. The bitchiest of the 'Valley girls' was there (by the way, she and this male professor get along well) and my partner made the even bigger mistake of asking the professor for the grade of a previous ignment. Neither of us were happy with the grade we received, so we tried to talk the professor into reconsidering the reasons for which he took some points from us. As soon as my partner opened his mouth to say something, Alpha Valley Girl was already rolling her eyes and turning her head to the opposite direction. I felt so disrespected by her body language and by the fact that she was seating right across from the professor and he did nothing. He said he wouldn't reconsider our grades, but still, that didn't have anything to do with the fact that one of his students was openly disrespecting other students in his very office. And it's not like this is the first time she does this in front of him. I haven't heard anyone else complain about these Valley Girls' attitudes, but I'm certainly angry AND humiliated. If they would have pulled this **** as undergraduate students in my faculty, I'm pretty sure any of the professors would have stopped them right on their tracks and they would have been scoffed by the other students as the spoiled whiners they are. (I mean, how come at this stage of their lives nobody has sat them down and explained to them that rolling their eyes while someone speaks denotes really bad manners.) But, ironically, on graduate school nobody seems to care, or at least nobody talks about it. It's like they forgot about politeness and respect for other people's questions and doubts, and just went right back to teenage-land. What I would like to know is how to let this girl know that she's being a jerk, in a polite and CLY way.