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