One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10)(11,16)(12,23)(13,26)(14,31)(15,20)(17,22)(18,29)(19,32)(21,37)(24,33)(25,34)(27,38)(28,35)(30,40)(36,39) involution — undirected(2,5)(6,8)(9,11,15,22)(10,16,20,17)(12,14,25,32)(13,27,30,21)(18,33,36,35)(19,23,31,34)(24,39,28,29)(26,38,40,37)(1,3,4,7)(2,6,5,8)(9,12,14,22,15,25,32,11)(10,17,19,23,20,16,31,34)(13,28,29,21,30,24,39,27)(18,33,26,37,36,35,40,38)(9,13,14,29,15,30,32,39)(10,18,19,26,20,36,31,40)(11,21,12,24,22,27,25,28)(16,33,34,37,17,35,23,38)(2,5)(6,8) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.