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