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