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