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