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