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