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