A 401(k) is just a container. Like real-world containers (those that are usually made out of metal), you can put (almost) anything you want in it.
Signing up for your employer's match is a great thing to do. Getting into the habit of saving a significant portion of your take-home pay early in your career is even better; doing so will put you lightyears ahead of lots of people by the time you approach retirement age. Even if you love your job, that will give you options you otherwise wouldn't have.
There is no real reason why you can't start out by putting your retirement money in a short-term money-market fund within that 401(k). By doing so you will only earn a pittance, probably not even enough to keep up with inflation in today's economic environment, but at this point in your (savings and investment) career, that doesn't really matter much. What really matters is getting into the habit of setting that money aside every single time you get paid and not thinking much of it. And that's a lot easier if you start out early, especially at a time when you likely have received a significant net pay increase (salaried job vs college student).
I know, everyone says to get the best return you can. But if you are just starting out, and feel the need to be conservative, then don't be afraid to at least start out that way. You can always rebalance into investment classes that have the potential for higher return -- and correspondingly higher volatility -- in a few years. In the meantime, you will have built a pretty nice capital that you can move into the stock market eventually.
The exact rate of return you get in the first decade matters a lot less than how much money you set aside regularly and that you keep contributing. See for example Your Investment Plan Means Nothing If You Don’t Do This by Matt Becker (no affiliation), which illustrates how it takes 14 years for saving 5% at a consistent 10% return to beat saving 10% at a consistent 0% return.
So look through what's being offered in terms of low-risk investments within that 401(k). Go ahead and pick a money-market fund or a bond fund if you want to start out easy. If it gets you into the habit of saving and sticking with it, then the overall return will beat the daylights out of the return you would get from a good stock market fund if you stop contributing after a year or two. Especially (but not only) if you do pick an interest-bearing investment, do make sure to pick one that has as low fees as you can possibly find for what you want, because otherwise the fees are going to eat a lot into your potential returns, benefiting the bank or investment house rather than yourself.
Just keep an open mind, and very strongly consider shifting at least some of your investments into the stock market as you grow more comfortable over the next several years. You can always keep a portion of your money in various interest-bearing investments to act as a cushion in case the market slumps.