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