The ornamental design for cap jewelry, as shown and described.
FIG. 1 is a front view of the cap jewelry according to the present design, wherein any portion in this or any other Figure illustrated in broken lines are for illustration of the environment of the invention, and forms no part of the claimed design;
FIG. 2 is a right side elevation view of the cap jewelry according to the present design, a left side elevation view being a mirror image thereof;
FIG. 3 is a rearview of the cap jewelry according to the present design;
FIG. 4 is a top plan view of the cap jewelry according to the present design;
FIG. 5 is a bottom plan view of the cap jewelry according to the present design; and,
FIG. 6 is a front view of the cap jewelry according to the present design showing the curved portion of the article as straightened.