You only tell the transform to translate in the direction you move. You also need to explicitly tell it to turn towards that direction. You can do this with the LookAt-method which will turn a transform to face a specific position:
transform.LookAt(transform.position + new Vector3(x, 0, z));
EDIT:
Now that your character is turning you also need to take into account that the method signature for Translate() is:
public void Translate(Vector3 translation, Space relativeTo = Space.Self);
This means that if you do not att the second parameter it will assume you want to move in the transform’s local space, i.e. positive x axis is the right hand side of your character. If this is not the intended behaviour then you should write this instead: