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