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