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