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