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