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