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