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