The ornamental design for a cover of an electronicdevice with surface pattern, as shown and described.
FIG. 1 is a perspective view of a cover of an electronic device with surface pattern showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a left side elevational view thereof; and,
FIG. 4 is an enlarged view thereof, of circled portion 4 in FIG. 2.
In FIGS. 1-3, the evenly segmented broken lines indicate portions of the cover of an electronic device with surface pattern that form no part of the claimed design. In FIGS. 2 and 4, the long-dash short-dash type broken lines represent the boundary of the portion of the cover of an electronic device with surface pattern that is shown on an enlarged scale in FIG. 4. The broken lines form no part of the claimed design.