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