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