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