CdS quantum dots (QDs) with improved luminescence properties places it among active area of research for their exploitation in appealing application in next generation opto-electronic devices and in photonics. We present here the tunability of emission spectra in CdS QDs in whole visible spectrum i.e. from violet to red region by proper choice of the synthesis temperature and photoluminescence excitation wavelength. Different luminescence behavior is observed at low temperature and at higher excitation energy. Raman spectra show no blue shift in longitudinal optical (LO) phonon bands due to phonon confinement with synthesis temperature. There is noticeable asymmetry in the line shape indicating the effect of phonon confinement which confirms the small crystallites of good quality.