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