@nm   extremely grateful

@nm  Thanks ! For simplicity,  furthermore I'd like to let (5435 + 3*sqrt(515793))^(1/3)=t, but fail.

subs((5435 + 3*sqrt(515793))^(1/3)=t,s1)

@tomleslie  This is good, but it seems to be less thorough than the above method of vv.

@vv  Thnaks!   expand is  more  stronger than simplify and value. It's weird.

@Carl Love 

I see, thank you！

@Pascal4QM Thanks it is useful!

@Carl Love 

When f (specific expression) is very complicated, in order to write concisely

@Carl Love  

I understand now, thank you so much！ Indeed,It can be generated by the transpositions (2, 3) and (3, 4)!

@dantopa   When we use the following code, we will get the right output. The example from vv.

I post  another problem of ChromaticNumber in the link below. 

 https://www.mapleprimes.com/questions/229567-Bug-Of-ChromaticNumber

@tomleslie Thanks and maybe you are right. I still not know  immanent cause.

@Carl Love  Extremely grateful

@Carl Love  Thank you very much!  Unfortunately，I am not still familiar for creating  Array inside loop.  I have a question :  How to save these graphs  based on  using  iterator codes rather than naive method of building lists inside loop.

.

@Carl Love  Thanks!  By testing in my computer, your codes cost 0.375 seconds .  My codes cost 0.672 seconds .

It's much better!   I read the help of  NonIsomorphicGraphs. I noticed one  option output=iterator . 

 So I use output=iterator in order to avoid costing large RAM when complete sequence of graphs  is formed at once.  Sometimes it  even causes Maple  to crash.

@vv  Maple 2020 can do that!

@ Christopher2222  when I first use mapleprimes I don't know why my question was deleted quickly