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