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