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