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