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)(11,18)(12,15)(13,21)(14,17)(16,22)(19,23)(20,24)(25,26,31,34)(27,32,30,40)(28,33,38,29)(35,36,37,39)(1,2,4,6)(3,5,8,7)(9,11)(10,15)(12,14)(13,19)(16,23)(17,18)(20,22)(21,24)(25,27,31,30)(26,32,34,40)(28,35,38,37)(29,39,33,36)(1,2)(3,5)(4,6)(7,8)(9,10,14,17)(11,15,12,18)(13,16,22,21)(19,23,20,24)(25,28,31,38)(26,29,34,33)(27,35,30,37)(32,39,40,36)(1,3,4,8)(2,5,6,7)(9,10)(11,18)(12,15)(13,16)(14,17)(19,24)(20,23)(21,22)(25,28)(26,33)(27,35)(29,34)(30,37)(31,38)(32,36)(39,40)(9,12,14,11)(10,15,17,18)(13,19,22,20)(16,24,21,23)(25,29,31,33)(26,28,34,38)(27,36,30,39)(32,37,40,35)(9,13,14,22)(10,16,17,21)(11,19,12,20)(15,23,18,24)(25,30,31,27)(26,32,34,40)(28,37,38,35)(29,39,33,36)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.