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