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