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