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