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