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