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