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