Yes. Look at the "startAnnotationMode API" section of the documentation. The code will look like this except you'll be generating your own color.
const mode = "highligh";
const options = {
defaultColor: "#b80000"
};
previewFilePromise.then(adobeViewer => {
adobeViewer.getAnnotationManager().then(annotationManager => {
annotationManager.startAnnotationMode(mode, options)
.then(result => console.log(result))
.catch(error => console.log(error));
});
});