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