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