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