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