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