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