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