One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,4)(3,7,8,6)(9,10,13,18)(11,20,22,15)(12,16,25,31)(14,17,27,19)(21,28,24,34)(23,29,36,33)(26,30,38,32)(35,40,37,39)(1,3,5,8)(2,6,4,7)(9,11,13,22)(10,15,18,20)(12,24,25,21)(14,23,27,36)(16,28,31,34)(17,33,19,29)(26,37,38,35)(30,40,32,39)(9,12)(10,16)(11,21,22,24)(13,25)(14,26)(15,28,20,34)(17,30)(18,31)(19,32)(23,35,36,37)(27,38)(29,39,33,40)(1,4,5,2)(3,6,8,7)(10,17)(11,22)(14,27)(15,29)(16,30)(18,19)(20,33)(21,24)(26,38)(28,39)(31,32)(34,40)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.