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