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