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