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