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