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