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