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