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