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