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