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