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