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