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