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