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