There are huge differences. And I have to diverge - color is not the biggest part. Many breeds share the same colors.
Here is how to distinguish breeds -
Body type/shape (you can tell the difference in a doberman and a saint bernard, right? Wing carriage, tail carriage, tightness of feather, fullness of feather, conformation of bird)
Comb (single, rose, v, buttercup, pea, walnut, etc)
Earlobe color (red, white)
Skin color (black, yellow, white)
Shank/Leg color (blue, slate, black, green, yellow, willow, pink/white)
Color (normal colors, breed specific colors, project colors that aren't accepted yet)
Eye color (orange, red, yellow, hazel, black/brown, etc)
Temperament (flighty, docile, friendly, lap chicken, noisy, quiet)
Rate of laying (hardly ever lays, sometimes lays, lays okay, prolific layer)
Color of eggs (Green/etc, blue, chalk white, white, cream, tinted, brown, chocolate/terra cotta)
Then, there are specific, distinguishing characteristics. Ameraucanas have muffs/beard, Araucanas have tufts, Polish/Houdans/Silkies/Spitzhaubens have crests, silkies/dorkings/faverolles have extra toes, brahmas/langshan/faverolles/cochins, sultans have feathered feet, cubalayas/sumatras/phoenix have long tails, etc
Each breed will have a unique background/purpose/acceptance date.
Really, the only way to become familiar with all the breeds is to study them, get exposed to them. Go to a the breeds section here on BYC and look around, or on feathersite.