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