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