Graphical means “about pictures, charts, or computer images,” not about words alone. A graphical display shows you information with drawings, icons, or graphs. On a computer, a graphical way of working is the kind where you tap pictures and buttons; the older kind was mostly typed words. You will see it in school IT and in talk about charts. Though actually, graphic without the -al can mean something else as well: “very clear and a bit shocking,” as in graphic violence. Graphical almost never means that; it stays with pictures and graphics. Designers more often say graphic design than graphical design. It is a slightly formal, school-and-computer word.