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