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