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