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