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