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