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