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