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