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