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