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