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