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