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