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