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)(13,14)(15,21)(16,25)(17,19)(18,22)(20,24)(23,27)(26,28) involution — undirected(6,9)(10,12)(14,19)(15,23)(16,18)(20,27)(21,28)(24,26) involution — undirected(1,2,3,4)(13,15,17,24)(14,20,19,21)(16,23,18,26)(22,27,25,28)(13,15,17,24)(14,21,19,20)(16,23,18,26)(22,28,25,27)(5,7,8,11)(6,10,9,12)(13,16,17,18)(14,22,19,25)(15,23,24,26)(20,27,21,28)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.