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