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