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