Sebastian Mueller's talk at Connected Data London in October 2019 focused on various tools and techniques for visualizing connected data, aimed at data scientists, engineers, project managers, and software developers. The presentation covered a range of visualization software options, their pros and cons, and highlighted the capabilities of specific libraries and methods for enhancing graph visualization, including automatic layouts and node customization. Real-world examples were provided, showcasing how to manipulate and transform graph data to enhance clarity and insight.