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