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