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