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