That looks like it might be the underside of the tank lid. It might be easier to tell the color from a picture of the outside of the toilet and use that in combination with the numbers in the tank.
Below are some colors put into words.
Aspen green - similar to sage green but darker, a dusty grey green
Biscuit - version of off-white, lighter than bone, less than almond.
Blond - very pale yellow, as light as biscuit but with a hint of yellow.
Blossom pink - not as bright as rue pink, a very light version of dusty rose.
Bayberry - similar to aspen green, but a little lighter. Darker than sage, but same hue.
Bermuda coral - similar to peach but with a little more brown/tan.
Bone - slightly darker than white. Basically an "off-white."
Candlelight - similar to tan but with a little less brown/tan.
Caribbean blue - similar to skyblue but with a little darker tint of navy blue.
Cerulean blue - similar to blue but with a little more grey - (close to Dresden blue).
Country grey - similar to gray but with a little darker tint of black.
Cream - similar to bone/almond but with a but with a little more tan but not as tan as innocent blush.
Desert bloom - similar to tan, peach version of tan.
Desert gold - similar to yellow but with a little tin of tan.
Dresden blue - similar to sky blue but with a little less navy (light blue) - (close to cerulean blue).
Euro White - is a shade darker than plain white.
Fawn beige - similar to tan but with a little more brown.
French vanilla - similar to blonde but with a little yellow tint.
Honeydew green - similar in hue to jade but much lighter.
Innocent blush - similar to almond but with a little more brown/tan.
Manchu yellow - similar to yellow but with a tint of tan - but not as much as desert gold.
Ming green - similar to green with a little less blue hue.
Mink - similar to fawn beige but with a tint of brown.
Mushroom - similar to bone but with a little more tan but not as dark as cream or innocent blush.
New Orleans blue - similar to light blue but with a little more blue color than sky blue.
Parchment - similar to fawn beige but with a little more tan/brown.
Peach bisque - similar to peach with a tint of tan.
Peach blow - similar to peach with a tint of salmon color. Peach blow is slightly darker than peach bisque.
Regency blue - similar to blue with a little grey.
Rosedawn - similar to bone with a little tin of pink/red.
Saffron yellow - similar to yellow, just a little lighter.
Salmon - similar to tan with a little peach tint.
Seafoam green - similar to sage with a tint more of green.
Shell - similar to peach bisque with a slightly lighter tint. It's in the light pink range.
Skylight blue - similar to light purple with a little more blue.
Sunrise yellow - similar to yellow but creamier.
Taupe by Kohler - seems American Standard's Classic Mink colors look virtually identical
Thunder grey - similar to grey but with more black.
Twilight blue - similar to blue with a little tint of grey.
Venetian pink - similar to pink but not as dark as blossom pink.
Warm white - similar to almond with a slightly yellow tint.