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