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