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