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