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