When you link to Excel you link to the DATA in the spreadsheet.
Colour is therefore not included.
Do as Strakmann suggests or you might even be able to utilise pootle flumps Excel Automation stuff in the MS Access code Bank (which can be found in a sticky at the top of the access topic (on the first 2 pages somewhere methinks)). Anyhow, if there arespecial rules for colouring then no doubt you'll be able to bodge something together with that. But beware, it's not going to be easy!