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