Blue?! No, seriously, I think the colour blue has to be a significant feature of any powerpoint background for a presentation on this excellent novel. #2 makes a very good point concerning the need to signal that there is something not quite right about the situation that Kira finds herself in. You also might like to think of the way in which the world in which Kira lives is depicted as being brutal and savage, as shown by the way that her mother had to fight to keep Kira from being left to die as a baby. So, something mysterious and/or something that reflects the danger of this world would be good places to start.