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