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