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