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