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