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