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