There may be several circumstances 1. If you refer to something of certain colour or colours, for example a. red flowers, which means the colour of the flowers is red, you can say “红花” or “红色的花” b. green trees, which means the colour of the trees is green, you can say "绿树" or “绿色的树” And so on. 2. If you use colour words with other meanings that are irrelevant with the colours themselves, there may be some certain usages, for example a. 红茶、绿茶 and 黑茶 refer to 3 kinds of tea, not 3 colours of the tea, so you can't say "红色的茶/红色茶" "绿色的茶/绿色茶" “黑色的茶/黑色茶” b. Green life, which refers to a healthy and low-carbon way of living, in Chinese you can say 绿色（的）生活 but 绿生活 is very odd c. 黄色(的)书籍、黄书 both refer to pornographic books And there are still many set phrases you have to memorize.

I would say "一本綠色的書". But it depends. For example I would say 一隻黑狗 一雙紅鞋 You can also say 一隻黑色的狗 一雙紅色的鞋

一个词或词组后加“”的“”，就可以作形容词用，形容词也要加“的”， 如： 美丽is a adj, 我们说：美丽的花，不说：美丽花，就是为了说起来更有节奏感。为了读起来有节奏感，我们会根据上下文的需要，把的字去掉或写出来。

它们都是对的 they all correct. 这是口语中的省略性表达

We tend to say a green cover book. 我们一般说一本绿色的书(绿色封面）