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