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