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