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