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