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