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