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