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