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