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