When a battery is connected to a wire there will be a non-zero field inside the wire and charges will flow.
For the charge carriers in a metal, the applied field superimposes a net drift velocity vd onto the random motion already there.
If the colored balls represent conduction electrons in a metal, in which direction is the applied field when the field is turned on?
If you turn on the field and watch the purple ball (which represents a typical electron) for a while, you should notice a net drift to the right. The field must therefore point to the left, because that would generate a force to the right on negative charges.