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