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