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