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