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