Right now there's no way to configure the format of the telegram message. What change would you have liked to make?
We considered having using the email subject format in the past and decided against it, because the point of the email subject is to change the way that your email reader groups messages. We figured that what you'd set for email is not necessarily what you'd want for telegram as the format cannot affect grouping in any way in telegram.
For example, you might want the date without the time in email subject so you get a thread per day, but that would be weird in telegram ... telegram itself supplies the date so you don't need it, but you probably do want to know the time.