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