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