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