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