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