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