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