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