not sure what a "Telegram" is. i assume the data is read into a byte array.
while Serial.print() doesn't know how to display "byte", it certainly knows how to display chars. so if if a value c-string is within the received buffer, it can be displayed by locating the beginning of the string and casting it as a char* (i.e. "(char*)"). make sure the c-string is terminated with a NULL, 0.
byte s [] = "how now brown cow";
Serial.println ((char*) &s [5]);