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