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