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