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