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