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