Why not run a Box-Tidwel test instead. You don't have to rely on graphical methods for this.

http://www.ats.ucla.edu/stat/stata/w.../statalog3.htm

If you suspect non-linearity from this one solution is to create an interaction term of the predictors times the natural log of that predictor. Then use these interaction terms (and the original predictors) to predict the original DV. If any of the terms are found to be signficant it suggests that term may be non-linear in predicting the DV.