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