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