Coded Aperture Snapshot Spectral Imaging (CASSI) systems capture the spatial and spectral information of a scene by measuring 2D coded projections on a focal plane array (FPA). Compressed sensing reconstruction algorithms are then used to recover the underlying spectral data cube. The quality of the reconstructions in CASSI is determined by the design of a set of block-unblock coded apertures. In this work, the block-unblock coded apertures in CASSI are replaced by colored coded apertures. The Restricted Isometry Property (RIP) of the colored CASSI is developed and the structure of the colored coded apertures is designed such that the RIP is better satisfied. Simulations show significant gain in the quality of reconstructions for the optimized colored coded apertures over that attained by traditional block-unblock coded apertures.