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