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