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