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