FIG. 1 is a perspective view of “cover of hand dryer” showing my new design thereof; FIG. 2 shows that a right side view thereof; FIG. 3 is a top view thereof FIG. 4 is a front side elevation view thereof; FIG. 5 is a bottom plan view thereof; FIG. 6 is a left side elevation view thereof; FIG. 7 is a rear perspective view hereof; and, FIG. 8 is another perspective view thereof.