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