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