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