Generally, adjectives of quantity and size precede others. I can't say why, except that was how it was ordered in Latin.
I want many big beautiful soft red silk hats. No commas.
Color and material are subset adjectives, and for that reason usually goes right before the set (hats) it modifies.
You don't need commas unless the adjectives don't modify each other.
I want many big beautiful soft red, green, purple and yellow silk hats.
How do you know if an adjective modifies another? Try using and between them. Red and green and purple and yellow doesn't change the meaning of the words, so they are "equal" (and get commas), but if you want a purplish green striped yellow spotted red hat, meaning changes with and, so you must order them the way you want them. A purplish-green striped, yellow-spotted (comma optional) red hat. (Does that make sense?)
Oh, in the time I typed this, others have given better answers, so I'll stop here.
Please know that the order of adjectives is still being debated.
This is one ordering I've found.
evaluation > size > shape > condition > human propensity > age > color > origin > material + attributive noun.
I myself would change this to number > size > evaluation > shape...
(French takes almost this order, I think, with the subsets following the noun. Je veux beaucoup de beaux grands chapeaux de soie rouge. I like the word "de". Less complicated.)
Oh, and, as in Latin, the order can be changed to emphasize or differentiate.