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