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