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