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