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)(11,18)(12,16)(13,22)(14,17)(15,21)(19,24)(20,23)(27,34)(32,39)(35,40)(36,37)(9,11)(10,15)(12,19)(13,20)(14,21)(16,23)(17,18)(22,24)(25,26,30,33)(27,35,34,40)(28,29,31,38)(32,36,39,37)(1,3,4,8)(2,5,6,7)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(25,27,31,37,30,34,28,36)(26,32,29,35,33,39,38,40)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(25,28,30,31)(26,29,33,38)(27,36,34,37)(32,35,39,40)(11,21)(15,18)(19,20)(23,24)(25,29,31,33,30,38,28,26)(27,35,37,39,34,40,36,32)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.