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