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