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)(11,15)(12,13)(14,16)(17,18)(19,24)(20,23)(21,22)(26,31)(28,32)(33,39)(36,40)(10,12)(11,16)(18,22)(19,20)(25,26,30,31)(27,28,35,32)(29,33,38,39)(34,36,37,40)(10,12)(14,15)(17,19,21,20)(18,23,22,24)(25,27,30,35)(26,32,31,28)(29,37,38,34)(33,36,39,40)(1,2)(3,5)(4,6)(7,8)(9,11,13,16)(10,14,12,15)(17,20,21,19)(18,23,22,24)(25,28,30,32)(26,27,31,35)(29,36,38,40)(33,34,39,37)(1,3,4,7)(2,5,6,8)(9,12,13,10)(11,15,16,14)(17,18)(19,24)(20,23)(21,22)(25,29,30,38)(26,33,31,39)(27,34,35,37)(28,36,32,40)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.