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