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