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