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)(15,20)(16,26)(17,28)(21,32)(22,34)(24,29)(25,39)(30,36)(31,37)(33,35)(38,40) involution — undirected(2,5)(6,8)(11,20)(13,28)(15,19)(16,31)(17,27)(21,35)(22,36)(24,40)(26,37)(29,38)(30,34)(32,33) involution — undirected(1,3,4,7)(2,6,5,8)(9,11,13,20,14,22,28,36)(10,15,17,19,18,30,27,34)(12,24,26,40,25,21,37,35)(16,32,23,38,31,29,39,33)(9,12,14,25)(10,16)(11,21,22,24)(13,26,28,37)(15,29)(17,23)(18,31)(19,33)(20,35,36,40)(27,39)(30,32)(34,38)(2,5)(6,8)(12,25)(16,31)(21,24)(23,39)(26,37)(29,32)(33,38)(35,40) 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.