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