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