FIG. 1 is an isometric view of a cover sleeve according to my design;

FIG. 2 is a front elevation view of the design of FIG. 1;

FIG. 3 is a rear elevation view of the design of FIG. 1;

FIG. 4 is a top elevation view of the design of FIG. 1;

FIG. 5 is a bottom elevation view of the design of FIG. 1;

FIG. 6 is an isometric view illustrating another embodiment of a cover sleeve according to my design;

FIG. 7 is a front elevation view of the design of FIG. 6;

FIG. 8 is a rear elevation view of the design of FIG. 6;

FIG. 9 is a top elevation view of the design of FIG. 6;

FIG. 10 is a bottom elevation view of the design of FIG. 6;

FIG. 11 is an isometric view illustrating another embodiment of a cover sleeve according to my design;

FIG. 12 is a front elevation view of the design of FIG. 11;

FIG. 13 is a rear elevation view of the design of FIG. 11;

FIG. 14 is a top elevation view of the design of FIG. 11;

FIG. 15 is a bottom elevation view of the design of FIG. 11;

FIG. 16 is an isometric view illustrating another embodiment of a cover sleeve according to my design;

FIG. 17 is a front elevation view of the design of FIG. 16;

FIG. 18 is a rear elevation view of the design of FIG. 16;

FIG. 19 is a top elevation view of the design of FIG. 16; and,

FIG. 20 is a bottom elevation view of the design of FIG. 16.

The interior of the article does not form a part of the claimed design. The dashed lines in FIGS. 16 and 19 represent stitching.