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