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