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