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