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