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