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