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