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