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