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