Here are some interesting links about careers of mathematics majors
whydomath.org You can find here some recent applications of mathematics in concrete ways to everything from the design of fast sailboats to understanding the neuroscience of human brains to medical imaging to space travel.
What do mathematicians do? This link is to a page by the American Mathematical Society. It provides further links to information about people who majored in mathematics and what they have done.
weusemath.com This link gives another view of how mathematically sophisticated people have found ways to put their mathematical skill into play.
Mathematics Careers This webpage is sponsored by the Mathematical Association of America. It has information and further links about careers in mathematics. One link on that page is career profiles, which gives a bunch of links to brief biographical sketches of people would majored in mathematics and subsequently pursued an extremely wide array of careers.