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)(15,21)(20,27)(22,23)(26,28)(5,6)(7,10)(8,12)(9,11)(14,18)(15,22)(16,24)(19,25)(20,27)(21,23) involution — undirected(1,2,3,4)(13,14)(15,20)(16,25)(17,19)(18,24)(21,27)(22,28)(23,26)(5,7,9,8)(6,10,11,12)(14,19)(18,25)(20,27)(26,28)(5,8,9,7)(6,10,11,12)(13,15)(14,20)(16,22)(17,21)(18,26)(19,27)(23,24)(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.