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