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