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