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