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