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