Try the tool listed below or one similar. Here is a link that might be useful: Color Matching Tool

I used Owens Corning's custom design web site to pick a type of shingle and color. You can have your contractor give you a price for each grade. Once you get to the web site select your house type then at the next page select the "custom" tab and then pick which shingle grade you are interested in and then below you will see all the shingles in that line. Select one and you will be amazed. You can save the pictures to file to show your contractor. Also you can experiment with siding and veneer types by selecting the "Collections" tab. I used this site to pick my siding color, type and color of shingles. Here is a link that might be useful: Owens Corning

Who is the manufacturer? I notice that Driftwood varies from say Owens Corning to GAF to other mfg shingles. Personally I think Driftwood is a great color for a shingle roof. It's neutral. It gives you flexibility. You will need to get the actual shingle(s) so you can see how it looks against your current house color if you aren't up to painting just yet. I also like Weatherwood shingle color. Also neutral.

Pick out colors or whites like you want. Paint on poster board, or buy the peel and stick color patches and put on poster board. Leave a white border all the way around the poster board, so it doesnt clash with the color you have now. Since you want the whole house the same color, then pick a color that goes in your kitchen with your cabinets etc first. Then try it in the rest of the house. The color in there now, does not go with your cabinets. It has way too much yellow in it. I would look for colors that have no yellow hues.