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