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