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