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