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