Abstract: The discipline of graph visualization produces pictorial representations of node-link structures. Much effort has been directed toward making such diagrams visually pleasing. A variety of aesthetic heuristics have been proposed, with the assumption that these will improve readability and understanding. We look at a perceptual basis for these heuristics, including Gestalt principles and Norman's emotional design framework. Next, we review the work to date on aesthetic heuristics and examine what has been done to evaluate these heuristics. We summarize this in a framework that outlines graph drawing heuristics, their perceptual basis, and evaluation status.