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)(13,14,18,19)(15,23,25,20)(16,21,27,28)(17,22,24,26)(5,7)(6,9)(8,12)(10,11)(13,15)(14,20)(16,26)(17,28)(18,25)(19,23)(21,24)(22,27) involution — undirected(1,2,3,4)(13,16)(14,21)(15,24)(17,25)(18,27)(19,28)(20,22)(23,26)(6,10)(9,11)(13,14,18,19)(15,20,25,23)(16,21,27,28)(17,26,24,22)(7,12)(9,11)(13,17,18,24)(14,22,19,26)(15,16,25,27)(20,28,23,21)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.