。
He swept his brush quickly across the canvas.
Literal
He [topic-は] paintbrush [object-を] canvas [to-に] swiftly ran.
絵筆 (えふで, 'paintbrush') is the specific art tool. カンバス is the loan 'canvas.' さっと is a mimetic adverb for a swift, smooth movement. 走らせた is the causative of 走る — literally 'made (the brush) run,' a beautiful idiom for rapid brushstrokes. The personification of the brush as running captures the artist's fluid movement.