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