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