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