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)(19,20)(23,24)(25,26,30,34)(27,31,32,28)(29,33,38,40)(35,39,37,36)(1,3)(2,6)(4,7)(5,8)(10,13)(14,16)(18,22)(23,24)(25,27,30,32)(26,28,34,31)(29,35,38,37)(33,36,40,39)(2,7)(3,8)(9,10)(11,14)(12,13)(15,16)(17,18,21,22)(19,23,20,24)(25,27)(26,31)(28,34)(29,37)(30,32)(33,36)(35,38)(39,40)(1,3)(2,4)(5,8)(6,7)(17,19,21,20)(18,23,22,24)(25,28,30,31)(26,32,34,27)(29,36,38,39)(33,37,40,35)(1,4)(2,3)(5,6)(7,8)(9,11,12,15)(10,14,13,16)(17,20,21,19)(18,24,22,23)(25,29)(26,33)(27,35)(28,36)(30,38)(31,39)(32,37)(34,40)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.