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