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