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