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