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