The forex market runs 24/5, but each trading day ends at 5pm New York time, when all positions held past that moment trigger a rollover. Positions are nominally closed at 5pm and reopened at the next-day settlement price, with the difference (swap) credited or debited to your account. You do not see this happen on the chart — it is purely an accounting operation.
Rollover is why you pay swap interest on holds and why Wednesday rollovers are triple-sized (to cover the weekend). Day traders who close before 5pm never see rollover at all, which is one reason certain scalping strategies can avoid any holding cost.