The ornamental design for bath toy organizer, as shown and described.
FIG. 1 is a front perspective view of a bath toy organizer in a closed position in accordance with the new design;
FIG. 2 is a top view thereof;
FIG. 3 is a rear view thereof; and,
FIG. 4 is a front view of a bath toy organizer in an open position and containing bath toys in accordance with the new design.
The broken lines showing of the bath toys is for the purpose of illustrating the use and environment of the bath toy organizer and forms no part of the claimed design.