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