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