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