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