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