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