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