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)(15,22)(16,26)(17,18)(20,28)(23,24)(25,27)(5,7)(6,9)(8,12)(10,11)(13,14,19,21)(15,23,25,20)(16,17,26,18)(22,24,27,28)(13,15,19,25)(14,20,21,23)(16,24,26,28)(17,22,18,27)(7,12)(9,11)(13,16)(14,17)(15,24)(18,21)(19,26)(20,22)(23,27)(25,28) involution — undirected(1,3,4,2)(6,10)(9,11)(13,17,19,18)(14,16,21,26)(15,22,25,27)(20,24,23,28)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.