Carneades is a computational model of argument, based on the state-of-theart of argumentation theory in philosophy. This article presents a diagramming method for Carneades, similar to Wigmore charts, and illustrates how to map legal evidence using this method. With suitable computer support, in the form of a special purpose argument diagram editor, users need not understand the mathematics of the computational model to make use of its features. Compared to a generic diagram editor, or even special purpose argument diagramming tools based only on informal models of argument, an argument diagramming tool based on the Carneades computational model of argument has the advantage of being able to inform users, in an intuitively comprehensible way, whether or not a claim satisfies a proof standard, given the evidence and other arguments which have been put forward by the parties. The presentation is entirely informal. No prior expertise in argumentation theory, mathematics or computer science is presumed.