I’m having trouble on analysing this sentence. Firstly I look to the end of the phrase and I’m supposing that the verb 透き通った is stating that the clear blue and long hair is transparent. Then I go back to the beggining of the sentence and understand that something gives a soft and pale impression, I guess that the “something” is the hair. I concluded that the translation should be:
A long and transparent light blue colored hair gives a pale and soft impression.
Haha, tell me about it. I think it took me 2 months to finish it, had to look up words every other sentence. Well, good luck with it, it’s super fun if you stick to it. ファイトですね