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)(11,19)(12,15)(13,17)(14,23)(16,21)(18,22)(20,24)(25,26,29,33)(27,31,36,40)(28,32,30,37)(34,38,39,35)(2,5)(6,8)(9,11)(10,15)(12,13)(14,20)(16,23)(17,19)(18,24)(21,22)(25,27,29,36)(26,31,33,40)(28,35,30,38)(32,34,37,39)(3,7)(6,8)(9,12,13,11)(10,16,17,24)(14,20,22,21)(15,18,19,23)(25,26)(27,34)(28,32)(29,33)(30,37)(31,38)(35,40)(36,39)(1,3,4,7)(2,6,5,8)(11,12)(15,19)(16,24)(20,21)(25,28,29,30)(26,32,33,37)(27,35,36,38)(31,34,40,39)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.