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