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