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