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