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