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