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