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