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)(11,17,18,24)(12,20,22,15)(14,21,23,19)(25,26,29,32)(27,33,35,40)(28,36,38,31)(30,37,39,34)(1,2)(3,6)(4,8)(5,7)(9,11,13,18)(10,14,16,23)(12,21,22,19)(15,24,20,17)(12,22)(15,20)(17,24)(19,21)(25,27,29,35)(26,30,32,39)(28,37,38,34)(31,40,36,33)(1,3,5,4)(2,6,7,8)(11,18)(14,23)(17,24)(19,21)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.