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