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