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