Let \(W,S\) be a Coxeter system realized as an irreducible reflection group in \(\mathbb{R}^n\). Denote by \(A=(H)\) the arrangement of reflection hyperplanes and by \(G_W\) the corresponding Artin group. The authors introduce some combinatorial complex \(X_W\) which is homotopically equivalent to the orbit space \((\mathbb{C}^n -\bigcup_{H \in A} \otimes \mathbb{C})/W\). They give an explicit formula for cohomologies of local systems on \(X_W\) associated with representations of \(G_W\).