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