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