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