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