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