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