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