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