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