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