One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,13,16)(11,14,17,21)(12,19,20,15)(18,24,23,22)(25,26,31,37)(27,38,42,33)(28,35,29,45)(30,36,32,47)(34,46,52,44)(39,53,40,49)(41,54,43,50)(48,55,51,56)(2,5)(6,8)(9,11)(10,14)(12,18)(13,17)(15,22)(16,21)(19,24)(20,23)(25,27,31,42)(26,33,37,38)(28,40,29,39)(30,41,32,43)(34,51,52,48)(35,53,45,49)(36,50,47,54)(44,56,46,55)(11,17)(14,21)(18,23)(22,24)(25,28,31,29)(26,34,37,52)(27,39,42,40)(30,44,32,46)(33,48,38,51)(35,36,45,47)(41,55,43,56)(49,50,53,54)(9,12,13,20)(10,15,16,19)(11,18,17,23)(14,22,21,24)(25,29,31,28)(26,35,37,45)(27,40,42,39)(30,44,32,46)(33,49,38,53)(34,36,52,47)(41,55,43,56)(48,50,51,54)(1,3,4,7)(2,6,5,8)(25,30,31,32)(26,36,37,47)(27,41,42,43)(28,44,29,46)(33,50,38,54)(34,45,52,35)(39,55,40,56)(48,53,51,49)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.