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)(11,13)(12,14)(15,16)(17,18,23,24)(19,20,21,22)(25,26,29,32)(27,33,34,30)(28,36,37,31)(35,38,40,39)(2,5)(3,7)(11,15)(13,16)(17,19,23,21)(18,20,24,22)(27,34)(28,37)(30,33)(31,36)(2,5)(6,8)(9,10,12,14)(11,13,15,16)(17,20,23,22)(18,19,24,21)(25,27)(26,30)(28,35)(29,34)(31,38)(32,33)(36,39)(37,40)(1,3)(2,6)(4,7)(5,8)(9,10)(11,13)(12,14)(15,16)(17,21,23,19)(18,20,24,22)(25,26)(27,33)(28,31)(29,32)(30,34)(35,39)(36,37)(38,40)(1,2)(3,6)(4,5)(7,8)(9,11,12,15)(10,13,14,16)(17,22,23,20)(18,19,24,21)(25,28)(26,31)(27,35)(29,37)(30,38)(32,36)(33,39)(34,40)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.