I'm a little late on this reply, but here are some ideas I have seen chapters do in the past:
1. Carnation pass- a few sisters will carry carnations to class or when walking around campus and pass them on to the next sister. It was really fun to randomly see a sister when walking to class and get a carnation
2. Pride day- have every member wear their favorite shirt with AXO letters to class on the same day. Or, ask them all to wear a specific shirt ie last years recruitment shirt. It shows unity and allows the campus to see the chapter as the amazing women I am very sure you are!
3. Badge attire- similiar to the pride day, wear badge attire and obviously your badge, the day after ritual/formal meeting.
4. Try and co-sponsor some major events on campus (appropriate events such as a lecture series, not a party). This will get your name out there as a chapter who is involved, who cares, and is diverse in its interests. Plus, you will be able to attach your name to the posters or flyers that will promote the event. This list of co-sponsored events will also be a great recruiting tool when trying to recruit active, diverse women.
I hope these ideas help!