I,m sure you are aware that there are 2 types of breakaway cables. The type with a flexible spring steel gate is usualy longer than the type with a solid metal gate as it must be looped around the tow bar attachment & clipped back on its self. The type with a sold bar to the clip is designed to clip direct to the tow bar attachement.
If its still to long you could use a short bungee round the hitch & around the cable to keep it off the ground,but not to tight as to impede it during manouvering