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