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