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