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