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