The effective potential of composite diquark fields responsible for color symmetry breaking in cold very dense QCD, in which long-range interactions dominate, is derived. The spectrum of excitations and the universality class of this dynamics are described.11.15. Ex, 12.38.Aw, 26.60.+c Recently, there has been considerable interest in the study of the color superconducting phase of cold dense QCD [1-10] (for recent reviews, see Ref.[11]). The color superconducting quark matter may exist in the interior of neutron stars, with baryon number densities exceeding a few times the normal nuclear density n 0 ≃ 0.17 fm −3 . Also, such matter could be created in accelerators by heavy ion collisions.The Ginzburg-Landau (GL) effective action method has been extremely successful in studying ordinary superconductivity of metals [12]. Recently, a similar approach has been utilized in the study of color superconductivity [3,4]. However, there the effective action was postulated based on symmetry and renormalization group arguments, and not derived from the microscopic theory, QCD.Following the original approach of Gorkov [12], it would be of a great interest to derive the effective action in color superconductivity directly from QCD. In this letter, we make a step in realizing this program and derive the effective potential for the order parameter of color superconductivity in cold dense QCD at such high baryon densities when the fermion pairing in the diquark channel dominates over that in the chiral one [1,2] and when long-range interactions dominate [4,5]. For this purpose, we will utilize the method of Ref. [13], which was originally used for the derivation of the effective action in quenched strong-coupling QED 4 (see also Ref. [14]) and then was successfully applied to QED 3 [15], quenched QED 4 in a magnetic field [16], and to some other models [17].The crucial feature in the dynamics of cold dense QCD, pointed recently in Refs. [4,5] (see also Ref.[6]), is the presence of the long-range interactions mediated by the unscreened gluon modes of the magnetic type. This point essentially distinguishes the dynamics of color superconductivity from that in the BCS theory of superconductivity in metals. In particular, this makes the derivation of the effective action in color superconductivity more complicated than the derivation of the GL effective action from the BCS theory.Our derivation of the effective potential in dense QCD will be based on the recent analysis of color superconductivity in the framework of the Schwinger-Dyson (SD) equations [7][8][9]. In this way, we will describe the universality class of the dynamics in cold dense QCD and, in particular, get insight into the character of the spectrum of excitations.As we shall see below, the universality class of the system at hand is that connected with long-range non-isotropic forces, producing a bifermion condensate. We will see that this class resembles (although does not quite coincide with) that of quenched QED 4 in a constant magnetic field [18,19]. The scaling ...