Graphical representations have long been associated with more efficient problem solving. More recently, researchers have begun looking at how representation may affect the information that students attend to and what they learn. In this paper we report on a study of how graphical representation may influence interaction between a human coach and a student engaged in analyzing argument texts. We compared coaching interaction with subjects working with a predefined graphical representation to subjects who developed their own representation. The predefined representation, with a better "cognitive fit", to the task, allowed subjects to do more work on their own. Coaching was more systematic and both more efficient and more effective.