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