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