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