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