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