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