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