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