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