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