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