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