One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(9,10)(11,18)(12,17)(13,14)(15,16)(19,24)(20,23)(21,22)(25,26)(27,32)(28,33)(29,37)(30,31)(34,38)(35,36)(39,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(10,16)(13,19)(17,18)(20,22)(26,31)(27,33)(34,37)(35,40) involution — undirected(9,11,15,12)(10,17,16,18)(13,20,19,22)(14,21,24,23)(25,27,30,33)(26,32,31,28)(29,35,38,40)(34,39,37,36)(1,3,4,7)(2,6,5,8)(9,12,15,11)(10,18,16,17)(13,22,19,20)(14,23,24,21)(25,28,30,32)(26,33,31,27)(29,36,38,39)(34,40,37,35)(9,13,15,19)(10,14,16,24)(11,20,12,22)(17,21,18,23)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,40)(37,38)(9,14)(10,19)(11,21)(12,23)(13,16)(15,24)(17,22)(18,20)(25,29)(26,34)(27,35)(28,36)(30,38)(31,37)(32,39)(33,40) 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.