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