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