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