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