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