One vertex per element, one color per generator, with an edge from x to x·s.
(6,7)(8,12)(13,14)(15,16)(17,18)(19,20)(21,22,26,28)(23,24,25,27)(2,4)(8,12)(10,11)(14,18)(16,20)(21,23)(22,27)(24,28)(25,26) involution — undirected(1,2,3,4)(5,6,9,7)(8,10,12,11)(13,15,17,19)(14,16,18,20)(21,24,26,27)(22,25,28,23)(5,7,9,6)(8,11,12,10)(13,16,17,20)(14,15,18,19)(21,25,26,23)(22,24,28,27)(5,8)(6,10)(7,11)(9,12)(13,15)(14,16)(17,19)(18,20)(21,24)(22,25)(23,28)(26,27) involution — undirectedA 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.