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