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