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