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