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