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