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