I claim the ornamental design for the hair styling device, as shown and described.
FIG. 1 is a perspective view of a hair styling device of the present invention;
FIG. 2 is a front view of a hair styling device of the present invention;
FIG. 3 is a rear view of a hair styling device of the present invention;
FIG. 4 is a top plan view of a hair styling device of the present invention;
FIG. 5 is a bottom plan view of a hair styling device of the present invention;
FIG. 6 is a left side view of a hair styling device of the present invention; and,
FIG. 7 is a right side view of a hair styling device of the present invention.
The pattern is partially shown for convenience of illustration. It is understood that the pattern in uniformly continuous over the surface of the hair styling device with the exception of the curler element.