For a more thorough understanding of what Ruma is, take a look at Ruma's "Introduction to Matrix" guide, which explains Matrix, "homeservers," and the role of Ruma in the larger Matrix ecosystem: https://www.ruma.io/docs/matrix/
Colors that match the website are also preferred: mustardy yellow, grays, and black. See the home page: https://www.ruma.io/
The "chat bubble" logo shown on the current home page is just a placeholder. The final design shouldn't attempt to mimic or relate to it in any way.
The attached Ruma logo image is the one currently used for the project's Twitter and GitHub accounts (https://twitter.com/ruma_io and https://github.com/ruma). It's a combination of the Matrix logo and the Rust logo (both also attached.) The final logo may want to take inspiration from the "industrial" look of the Rust logo.
As a possible literal representation of Ruma, the logo could be a house with telephone wires extending out on either side of it, to show it being networked to other homes. The idea is that Ruma serves as the user's "home base," and simultaneously connects them into the global chat network. This is just one idea, and the final logo does not need to use it or be a literal representation at all.
Really the only hard requirement on the logo is that it have both a simple image that would be useable as a favicon and the text "Ruma" beside it.
A font that leans more toward a classic, elegant look is preferred. The logo should not be cartoony or cutesy. It should evoke technology, power, and performance.