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