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