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