あなたは英語力をいかした仕事をするべきだって英語でなんて言うの？

These are two different ways of explaining about your personal situation.

"A good job for you..." This indicates something that you are saying that something is good for someone.

"...will make good use of your ability to speak English" This gives the reasons why it is a good job.

You speak English so well that you could get a really good job that uses good English skills.
Your English skills is high enough to get a job using them.
If I were you, I would find a job that needs someone fluent in English.
There are many companies that could use your great English skills. I bet you could easily find a job with one of them.
If you want my advice, I would tell you to try for a job that needs someone with your good English skills.

"You should get a job which utilizes your English"
This phrase is expressing you should get a job that will use English, implying you can already speak good English, to 'utilize' this is to make effective and practical use of a certain skill you may have, in this case being able to speak English.

To someone who is fluent in English, you want to tell them that they should get a job that makes good use of their English ability. You use one of the suggested statements above according to your scenario.

Speaking and understanding English is a very popular skill that a lot of employers look for while hiring. If you think someone has very good English language skills, both speaking and understanding of the language you could suggest they get a job that allows them to use their skills every day or ask if they have ever considered it, as they might not be very comfortable using their language skills.

When you want to tell someone that they should get a job that makes good use of their English proficiency; then you may say it in the following ways:
-You should get a job where you can make use of your good English
-I think you should get a job that makes good use of your English skills