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