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