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