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