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