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