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