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