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