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