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