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