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)(9,11,13,19)(10,14,16,17)(12,18,21,24)(15,22,20,23)(25,26,31,33)(27,34,37,40)(28,29,30,38)(32,35,39,36)(1,3,5,4)(2,6,7,8)(25,27,30,36,31,37,28,35)(26,32,29,34,33,39,38,40)(9,12,13,21)(10,15,16,20)(11,18,19,24)(14,22,17,23)(25,28,31,30)(26,29,33,38)(27,35,37,36)(32,34,39,40)(1,4,5,3)(2,6,7,8)(11,19)(14,17)(18,24)(22,23)(25,29,30,33,31,38,28,26)(27,34,36,39,37,40,35,32)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.