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