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)(13,25)(14,30)(15,18)(17,28)(19,34)(20,31)(21,29)(22,33)(24,32)(26,27)(35,36)(37,38)(39,40) involution — undirected(2,5)(6,8)(9,11,15,22)(10,16,18,33)(12,24,27,39)(13,29,30,20)(14,31,25,21)(17,34,35,37)(19,36,38,28)(23,32,26,40)(1,3,4,7)(2,6,5,8)(9,12,25,36,15,27,14,28)(10,17,30,26,18,35,13,23)(11,19,31,39,22,38,21,24)(16,32,29,37,33,40,20,34)(9,13,25,10,15,30,14,18)(11,20,31,16,22,29,21,33)(12,26,36,35,27,23,28,17)(19,37,39,40,38,34,24,32)(2,5)(6,8)(12,27)(17,35)(19,38)(23,26)(24,39)(28,36)(32,40)(34,37) 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.