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