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