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