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