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