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