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