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