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)(15,24)(16,20)(17,22)(18,23)(19,27)(21,25)(26,28) involution — undirected(1,2)(3,4)(6,9)(10,12)(13,15,18,16)(14,20,23,24)(17,25,19,26)(21,22,28,27)(2,4)(13,16,18,15)(14,21,23,28)(17,25,19,26)(20,22,24,27)(2,4)(13,17,18,19)(14,22,23,27)(15,25,16,26)(20,28,24,21)(5,7,8,11)(6,10,9,12)(15,16)(20,24)(21,28)(25,26)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.