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