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