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