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