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