Вы можете переименовать уровни из cut
автоматически, используя регулярное выражение
x = runif(100, 0,100)
y = cut(x, breaks = (0:10)*10)
levels(y)
# [1] "(0,10]" "(10,20]" "(20,30]" "(30,40]" "(40,50]" "(50,60]" "(60,70]" "(70,80]"
# [9] "(80,90]" "(90,100]"
levels(y) = sub(".(.+),(.+).", "\\1-\\2" , levels(y))
# [1] "0-10" "10-20" "20-30" "30-40" "40-50" "50-60" "60-70" "70-80" "80-90" "90-100"