One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10,15,26,13,19,14,18)(11,16,20,28,22,31,23,30)(12,17,25,32,24,33,27,37)(21,29,36,39,35,40,34,38)(1,2)(3,7)(4,8)(5,6)(9,11,14,23,13,22,15,20)(10,16,18,30,19,31,26,28)(12,21,25,36,24,35,27,34)(17,29,32,39,33,40,37,38)(1,3,5,4)(2,7,6,8)(11,20)(14,15)(16,28)(18,26)(21,34)(22,23)(25,27)(29,38)(30,31)(32,37)(35,36)(39,40)(1,4,5,3)(2,7,6,8)(9,12,13,24)(10,17)(11,21,22,35)(14,25,15,27)(16,29)(18,32)(19,33)(20,34,23,36)(26,37)(28,38)(30,39)(31,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.