Illusion knitting stripes are closer to garter stitch than they are to stocking stitch. Garter stitch ridges and stitches form a square grid and, in our experience, a design on a square grid works much better for illusion knitting than a normal stocking stitch (intarsia) grid.
We used our Square to Eternity design, overlaid it with a square grid and turned it into an illusion chart (as described in Charting Basics)
In illusion knitting, the stripes are in two colours and each stripe is made up of two rows. The right side of every stripe is knit, whichever colour is being used. You can completely forget about the right side rows as they are always plain knit.
All the action takes place on the second row of the stripe (which is the wrong side of the work). You only need a chart for the wrong side rows. On the chart, white stitches are purl, coloured stitches are knit, using the colour for the stripe you are working.