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