For this puzzle, we have an 11×11 grid and the letters B, C, H, I, L, N, O, P, S, T, and U. Every row and column and both main diagonals contain each of the 11 letters exactly once. In addition, the grey shaded areas together contain the letters in BIBLIOPHILISTIC, the blue shaded areas each contain a five-letter word or phrase (one is TULIP, the other is IN PUB), the red shaded areas each contain a four-letter word (COUP and SOUL), and the green shaded areas each contain a three-letter word (HUB, NUT, TON and UNI).
When you figure out the solution, you can check it here, and get the cache coordinates.
Be sure not to go on private property on the way to or from the cache.