For any domino to go next to , it must have a side with either 1 or 5 pips on it, so cannot be next to it.
The only other domino with a 1 is , so this must go next to the 1, producing . Then, the only other domino
with a 2 must go next to this, producing . This means that cannot be next to .
The other dominos can all be a neighbour of , as the diagrams below show: