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