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