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