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