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