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