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