I don't know of a way to do this interactively except to create a dashboard (maybe someone else does?), but you could make a fairly simple script to order them any way you like.  Add a local data filter to your platform and performing the analysis for a single level of your By element, and then copy/paste the script into a New Window script of your own:
 
Names default to here(1);
//open sample data
dt = Open("$Sample_data/big class.jmp");
//New window and V list box will create a window with each analysis below the previous one
win = New Window("Analysis",
	V List Box(
	
		//copy this script from the platform you used after adding a local data filter
		Bivariate(
			Y( :height ),
			X( :weight ),
			Local Data Filter(
				Close Outline( 1 ),
				Add Filter(
					columns( :age ),
					Where( :age == 14 ),
					Display( :age, N Items( 6 ) )
				)
			)
		),
		
		//then add the comma (previous line), and paste it again, changing the data filter
		Bivariate(
			Y( :height ),
			X( :weight ),
			Local Data Filter(
				Close Outline( 1 ),
				Add Filter(
					columns( :age ),
					Where( :age == 13 ),
					Display( :age, N Items( 6 ) )
				)
			)
		),
		Bivariate(
			Y( :height ),
			X( :weight ),
			Local Data Filter(
				Close Outline( 1 ),
				Add Filter(
					columns( :age ),
					Where( :age == 15 ),
					Display( :age, N Items( 6 ) )
				)
			)
		)
	)
);
//Now, if you want, you can hide all of the data filters:
(win << XPath("//OutlineBox[@helpKey='Data Filter']")) << Visibility("Hidden")
 I did just submit a wish list request for one way to make this easier:Respect value ordering in 'By' variable