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