I know there ARE 8 dimensions, I wouldn't doubt if there was 83748237483 dimensions, to indicate a point in the nth dimension it's just

(x,x,x,x,x,n...)

But to visually represent a dimension we don't already know is utterly impossible, I can see the fact that one dimension is

One arrow pointing up down OR left right

Two dimension is Up down left right,

Three dimension is Up down left right, forward back

But 4th dimension? You can't