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