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