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