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