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