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