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