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