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