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