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)(29,42)(33,38)(36,39)(40,54)(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)(32,44)(33,38)(34,43)(45,47)(46,51)(48,52)(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)(28,38)(29,43)(30,31)(33,41)(34,42)(35,44)(36,47)(37,51)(39,45)(40,48)(46,49)(50,55)(52,54)(53,56)(9,12,15,14)(10,17,20,19)(11,22,23,13)(16,24,21,18)(25,27,30,35)(26,32,31,44)(28,39,41,36)(29,37,42,49)(33,47,38,45)(34,46,43,51)(40,53,54,50)(48,56,52,55)(1,3)(2,5)(4,7)(6,8)(9,13)(10,18)(11,12)(14,23)(15,22)(16,17)(19,21)(20,24)(25,28,30,41)(26,33,31,38)(27,36,35,39)(29,40,42,54)(32,45,44,47)(34,48,43,52)(37,50,49,53)(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)(28,40)(30,42)(31,43)(32,46)(33,48)(35,49)(36,50)(38,52)(39,53)(41,54)(44,51)(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.