We claim the ornamental design for a switch lockout device, as shown and described.
FIG. 1 is an upper perspective view of the switch lockout device, shown with the cover in the open position and the adjustable cleat in the extended position;
FIG. 2 is a lower perspective view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a front elevational view thereof; and,
FIG. 8 is a rear elevational view thereof.
The portions of the switch lockout device shown in broken lines are for illustrative purpose only and form no part of the claimed design.