Your next hire or colleague should be someone who doesn't look like you. I know a lot of people aren't in a position who are directly hiring, but almost anybody can indirectly influence hiring. You can still have input on who your next colleague is.
There are a lot of small things you can do, like encouraging the HR department to advertise your job listings in places with an audience that doesn't match your current employee structure — the YWCA, Women in Tech, the Urban League. There are tons of ways you could reach out to communities that maybe you're inadvertently ignoring right now.
Volunteering is a great way to recruit. Anytime you attend a community group, if there's an appropriate venue, say, "Hey, my company's hiring for a bunch of different positions. Come talk to me about it."
Depending on the relationships you have with people who do have hiring power, talk with them directly: "Here are great candidates we could reach out to. Here are some training programs that may be able to funnel into what we're doing."
There have been studies that show if a person of the majority at a company advocates for people in a minority, they're seen as a good citizen. They gain points for that within the company structure. And there are a dozen of studies I could cite that show a direct correlation between a more diverse workforce, and better bottom line for the company. If the moral imperative isn't doing it for you, there's money.
There's a lot that's wrong in the world right now, but this particular idea is local and it's direct. This is something people can do where you're just putting in a little bit of your time, but making a huge difference in someone's life.