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