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