To signal a desire for learning, do cool things that require you to learn and do more than the job requires. Employers are, in general, sort of like archeologists: They study artifacts to understand the people who made them. So make artifacts that demonstrate you like to learn things.
Is there a way to cultivate curiosity? To start with, you want to avoid situations that suppress it. How much does the work you're currently doing engage your curiosity? If the answer is "not much," maybe you should change something.