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