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