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