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