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