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