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