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