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