This is my favorite Spreadsheet::WriteExcel source of examples listed and grouped together in a nice way here at this link, it got a couple of examples about colors, you can even programmatically control cells to display colors based on conditions regarding the contents they have, like red for negative values, blue for zero and green for positive values or any other combination of colors and conditions.

Probably you meant automatic resizing of columns to the size of the longest string a cell in that column can have. There's a function called Autofit. However get yourself familiarized with formats in Spreadsheet::WriteExcel so you can explore the multitude of other options you can get.