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