What you need to do is edit the stylesheet for the cart template you are using and remove the display: none line for the categories div.
e.g. if you were wanting to do this for the modern template, in the modern template folder edit the style.css file.
And change the following
Code:
#order-modern #categories {
display: none;
width: 75%;
margin: 10px auto 0 auto;
padding: 10px 0 10px 15px;
background-color: #666;
text-align: center;
-moz-border-radius: 5px;
-webkit-border-radius: 5px;
-o-border-radius: 5px;
border-radius: 5px;
}
to this:
Code:
#order-modern #categories {
width: 75%;
margin: 10px auto 0 auto;
padding: 10px 0 10px 15px;
background-color: #666;
text-align: center;
-moz-border-radius: 5px;
-webkit-border-radius: 5px;
-o-border-radius: 5px;
border-radius: 5px;
}
After making this change, be sure and shift reload the page in order for the new style sheet to load and the categories will show by default now on every page that uses them.