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