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