Option Explicit
Sub test()
Dim ws As Worksheet, c As Chart, s As Series, r As Range
Set ws = Worksheets("Tableaux horaires impairs")
Set c = ws.ChartObjects(1).Chart
For Each s In c.SeriesCollection
s.Delete
Next s
For Each r In ws.Range("D1:" & ws.Range("IV1").End(xlToLeft).Address)
Set s = c.SeriesCollection.NewSeries
With s
.Name = r
.Values = ws.Range("C8:C88")
.XValues = ws.Cells(8, r.Column).Resize(81, 1)
End With
Next r
With c.Axes(xlCategory)
.MinimumScale = 0
.MaximumScale = Application.Max(ws.Range("D8").Resize(81, ws.Range("IV1").End(xlToLeft).Column - 3))
End With
End Sub